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United States Patent |
5,664,836
|
Takagi
|
September 9, 1997
|
Reclining device for vehicle seat
Abstract
A reclining device for a vehicle seat, which has a base arm and an upper
arm rotatably connected via a shaft to the base arm, with an arcuate
inwardly toothed portion formed in the upper arm. A lock gear member is
rotatably supported on a pin fixed to the base arm, having an outwardly
toothed portion to be meshed with the arcuate inwardly toothed portion of
upper arm. The lock gear member is operatively connected via a cam plate
and interlocking elements to an operation lever. Thus, motion of the lock
gear member is confined to rotation about the pin, without wobbling
therein, and further the lock gear member is moved via those cam plate and
interlocking elements by handling the operation lever so as to positively
bring the outwardly toothed portion to and out of meshed engagement with
the inwardly toothed portion.
Inventors:
|
Takagi; Genjiro (Akishima, JP)
|
Assignee:
|
Tachi-S Co., Ltd. (Tokyo, JP)
|
Appl. No.:
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624090 |
Filed:
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March 29, 1996 |
Current U.S. Class: |
297/367; 297/369 |
Intern'l Class: |
B60N 002/20 |
Field of Search: |
297/367,369
|
References Cited
U.S. Patent Documents
3641838 | Feb., 1972 | Turner | 297/369.
|
3737946 | Jun., 1973 | Giuliani | 297/367.
|
3879802 | Apr., 1975 | Werner | 297/367.
|
4082352 | Apr., 1978 | Bales et al. | 297/367.
|
4085969 | Apr., 1978 | Nakane et al. | 297/367.
|
4087885 | May., 1978 | Gillentine | 297/367.
|
4103970 | Aug., 1978 | Homier | 297/367.
|
4188064 | Feb., 1980 | Cheshire | 297/367.
|
4348050 | Sep., 1982 | Letournoux et al. | 297/367.
|
4384744 | May., 1983 | Barley | 297/367.
|
4505515 | Mar., 1985 | Wilking et al. | 297/362.
|
4523786 | Jun., 1985 | Letournoux et al. | 297/367.
|
4758046 | Jul., 1988 | Cousin et al. | 297/367.
|
4770464 | Sep., 1988 | Pipon et al. | 297/367.
|
4874205 | Oct., 1989 | Arefinejad et al. | 297/367.
|
4997223 | Mar., 1991 | Croft | 297/367.
|
5161856 | Nov., 1992 | Nishino | 297/367.
|
5547254 | Aug., 1996 | Hoshihara | 297/367.
|
5547255 | Aug., 1996 | Ito et al. | 297/367.
|
5558402 | Sep., 1996 | Yamada | 297/367.
|
5558403 | Sep., 1996 | Hammoud et al. | 297/367.
|
5588705 | Dec., 1996 | Chang | 297/367.
|
5590931 | Jan., 1997 | Fourrey et al. | 297/367.
|
Foreign Patent Documents |
2254199 | Jul., 1975 | FR | 297/367.
|
2364754 | Aug., 1974 | DE | 297/367.
|
60-135338 | Jul., 1985 | JP.
| |
2177908 | Jul., 1990 | JP.
| |
1038878 | Aug., 1966 | GB | 297/367.
|
2117440 | Oct., 1983 | GB | 297/367.
|
Primary Examiner: Cuomo; Peter M.
Assistant Examiner: White; Rodney B.
Attorney, Agent or Firm: Browdy and Neimark
Claims
What is claimed is:
1. A reclining device for a vehicle seat, which includes an upper arm to be
fixed to a seat back of the seat and a lower base arm to be fixed to a
seat cushion of the seat, said upper arm being rotatable via a shaft with
respect to said lower base arm, said reclining device comprising:
an arcuate inwardly toothed portion which is formed in said upper arm,
generally along a circle having a center at an axis of said shaft;
a lock gear means having one end portion supported rotatably upon a pin
which is fixed to said lower base arm such as to be disposed apart from
said shaft, and further having another end portion formed with an
outwardly toothed portion, wherein said lock gear means is rotatable about
said pin to bring said outwardly toothed portion to and out of a meshed
engagement with a part of said arcuate inwardly toothed portion of said
upper arm, to thereby lock and unlock said upper arm with respect to said
lower base arm;
an operation lever having a base end portion rotatably connected to said
shaft;
a biasing means for normally biasing said operation lever to a non-use
position; and
an interlocking means arranged between said lock gear means and said
operation lever, said interlocking means including:
a cam means rotatably provided on said shaft, said cam means having a cam
end for contact with said lock gear means;
a guide means for guiding said lock gear means in a direction to disengage
said outwardly toothed portion of the lock gear means from said arcuate
inwardly toothed portion of said upper arm, said guide means comprising a
first guide means projected from said lock gear means and a second guide
means for engagement with said first guide means and said operation lever,
wherein said second guide means is so interlocked with said operation
lever that rotation of the operation lever permits said first guide means
to cooperate with said second guide means in an engagement relation
therewith so as to cause disengagement of said outwardly toothed portion
from said arcuate inwardly toothed portion, and
a connecting means for connecting said cam means to said operation lever,
wherein said cam means is normally retained under a biasing force of said
biasing force of said biasing means, causing said cam end to pressingly
contact said lock gear means, thereby retaining said outwardly toothed
portion of said lock gear means in a meshed engagement with a part of said
arcuate inwardly toothed portion, and wherein, when said operation lever
is rotated about said shaft from said non-use position, said cam means is
rotated about said shaft in a direction to bring the cam end thereof out
of contact with said lock gear means, while at the same time, said lock
gear means is caused by said guide means to rotate about said pin to bring
the outwardly toothed portion thereof out of the meshed engagement with
said arcuate inwardly toothed portion.
2. The reclining device as defined in claim 1, and wherein said lock gear
means is of an elongated shape and disposed such as to extend generally in
a horizontal direction intersecting a diameter of said circle along which
said inwardly toothed portion is formed in the upper arm.
3. The reclining device as defined in claim 1, wherein said lock gear means
has, defined at an upper side thereof, a contact area upon which said cam
end of said cam means is to be contacted.
4. The reclining device according to claim 3, wherein said contact area is
so sloped as to facilitate smooth riding of said cam end thereon.
5. The reclining device as defined in claim 1, wherein said first guide
means has a projected guide portion formed on said lock gear means and
said second guide mean has an engagement notch formed in said cam means
with such an arrangement that, when said operation lever is at said
non-use position, said engagement notch is disengaged from said projected
guide portion, whereas when said operation lever is rotated about said
shaft from said non-use position, said cam means is simultaneously caused
to rotate about the same shaft to bring said engagement notch to
engagement with said projected portion, and that, with further rotation of
the operation lever, said lock gear means, which is engaged with said
engagement notch as the projected guide portion thereof, is caused to
further rotate about said pin, thereby bringing the outwardly toothed
portion thereof out of the meshed engagement with said arcuate inwardly
toothed portion of said upper arm.
6. The reclining device as defined in claim 5, wherein said projected guide
portion of said lock gear means is disposed on a circle along which said
engagement notch is displaced with rotation of said cam means relative to
said shaft.
7. The reclining device as defined in claim 1, wherein said first guide
means has a projected guide portion formed on said lock gear means, said
projected guide portion being inserted slidably through said guide hole,
and said second guide means has an arcuate guide hole formed in the base
end portion of said operation lever and a projected guide portion, with
such an arrangement that, when said operation lever is at said non-use
position, said projected guide portion is positioned at one extremity of
said arcuate guide hole to place said lock gear means in the meshed
engagement with a part of said arcuate inwardly toothed portion, whereas
when said operation lever is rotated about said shaft from said non-use
position, said projected guide portion is simultaneously slid along said
arcuate guide hole, thereby causing said lock gear means to rotate about
said pin, bringing the outwardly toothed portion thereof out of the meshed
engagement with said arcuate inwardly toothed portion.
8. The reclining device as defined in claim 7, wherein said arcuate guide
hole is so formed to have a slant curvature relative to a center of
rotation of said operation lever, so that rotation of said operation lever
from said non-use position causes said projected guide portion of said
lock gear means to be slid along said arcuate guide hole from said one
extremity thereof so as to cause rotation of said lock gear means about
said pin in a direction to bring said outwardly toothed portion out of
contact with said arcuate inwardly toothed portion.
9. The reclining device as defined in claim 1, wherein said base end
portion of said operation lever is so formed as to expand upwardly,
wherein said operation lever is rotatably supported, at a lower end part
of such base end portion thereof, upon a pin which is fixed to said lower
base arm at a point apart from said shaft, wherein said first guide means
has a projected guide portion formed on said lock gear means, and said
second guide means has an arcuated guide hole formed in an upper part of
said base end portion of said operation lever, wherein said projected
guide portion is slidably inserted through said arcuate guide hole,
and wherein there is provided a link means for linking said base end
portion of said operation lever to said cam means via said connecting
means, said linking means being rotatably supported on said shaft.
10. The reclining device as defined in claim 9, wherein said arcuate guide
hole is so formed to have a slant downward curvature relative to said pin
associated with said operation lever, so that rotation of said operation
lever from said non-use position causes said projected guide portion of
said lock gear means to be slid along said arcuate guide hole from said
one extremity thereof, whereby said lock gear means is rotated about said
pin associated therewith in a direction to bring said outwardly toothed
portion out of contact with said arcuate inwardly toothed portion.
11. The reclining device as defined in claim 9, wherein said link means
comprises a link member having an upper portion rotatably supported on
said shaft and a lower portion connected to said base end portion of said
operation lever, wherein said connecting means comprises a connecting lug
projected from the upper portion of said link member, said connecting lug
being connected to said cam means, and wherein said base end portion of
said operation lever is arranged such that said arcuate guide hole is
disposed from said pin at a distance greater than a distance between said
upper and lower portions of said link member.
12. The reclining device as defined in claim 11, wherein said lower portion
of said link member is connected via a pin to a connecting hole formed in
the upper part of said base end portion of said operation lever.
13. The reclining device as defined in claim 9, wherein said base arm has,
formed therein, an escapement hole for allowing said guide pin of said
lock gear means to be freely moved therein.
14. The reclining device as defined in claim 1, wherein said connecting
means comprises a connecting lug projected integrally from said base end
portion of said operation lever, and wherein said connecting lug is
connected to an upper end portion of said cam means.
15. The reclining device as defined in claim 1, wherein said biasing means
comprises a spring extended between one free end portion of said operation
lever and said lower base arm.
Description
BACKGROUND OF INVENTION
1. Field of the Invention
The present invention relates to a reclining device for use in a vehicle
seat, which is operable to adjust the angle of inclination of a seat back
with respect to a seat cushion of the seat.
2. Description of Prior Art
Adjustment of a reclining device in a vehicle seat is effected through
locking and unlocking operation between a movable upper arm and a
stationary lower base arm thereof so that a seat back fixed on the movable
upper arm may be adjustably inclined relative to a seat cushion to which
the base arm is fixed, in order that a passenger on the seat can take a
proper seating posture. One of the locking mechanisms in this reclining
device is known from the Japanese Laid-Open Patent Pub. no. 60-135338.
Referring to FIGS. 1(A) and 1(B), this type of locking mechanism uses an
inwardly toothed lock portion (24') formed in a stationary lower base arm
(12') of reclining device, which is fixed to a seat cushion (not shown),
and a movable gear block member (25') having an outwardly toothed portion
(25'a), which is movably provided at an upper movable arm (14') of same
reclining device, the upper movable arm (14') being fixed to a seat back
(not shown).
The upper arm (14') is rotatable about a shaft (16') relative to the base
arm (12'). Operation of a cam (34') provided on the shaft (16') causes the
gear block member (25') to move rectilinearly along and between two guide
plates (G) (G) fixed to the upper arm (14') in a diametrical direction
towards and away from the axis of shaft (16') so that the outwardly
toothed portion (25'a) of gear block member (25') may be brought in meshed
engagement with the inwardly toothed portion (24'), and thus, the upper
arm (14') (seat back) can be locked at a selected point with respect to
the lower arm (12') (seat cushion).
However, in this prior art, to insure smooth sliding movement of the gear
block member (25'), a clearance (R) is provided between the guide plate
(G) and gear block member (25'), and the cam (34') contacts and supports a
small local part of the gear block member (25'). These factors may result
in the gear block member (25') being inclined on such small contact point
of cam (34') within both lateral clearances (R) (R) given on the opposite
sides of gear block member (25'), as shown in FIG. 1(B), when a great
force (F) is applied to both mutually meshed inwardly and outwardly
toothed portions (24') (25'a) respectively of the base arm (12') and gear
block member (25'). As a consequence of such inclination, the movable gear
block member (25') is not completely and evenly meshed with the inwardly
portion (24') due to the creation of meshed and non-meshed parts (X) (Y)
between those two toothed portions. (24') (25'a), as in FIG. 1(B), and a
load is intensively exerted on the meshed part (X), which reduces the
strength of both toothed portions (24') (25'a). Further, although the
clearance (R) is designed to a minimum degree, it is not only difficult
technically and cost-wise to minimize such clearance (R) with a precision
during a mass-production assembling process, but also it is the matter of
fact that even a slight inclination of the gear block member (25') is
magnified through the concurrent inclination of the upper arm (14') and
transmitted to a passenger on the seat as an appreciable inclination of a
seat back fixed to the upper arm (14'), thus resulting in a substantial
unstable wobbling of the seat back and making the passenger uneasy and
uncomfortable therewith.
SUMMARY OF THE INVENTION
In view of the above-stated drawbacks, it is a primary purpose of the
present invention to provide an improved reclining device for vehicle seat
which prevents a wobbling of seat caused from the inclination of lock gear
member in a locked state within the reclining device.
In order to achieve such purpose, the reclining device in accordance with
the present invention, basically comprises:
an arcuate inwardly toothed portion which is formed in an upper arm along a
circle having a center at an axis of a shaft;
a lock gear means having one end portion supported rotatably on a pin fixed
to a lower base arm, and another end portion formed with an outwardly
toothed portion, the lock gear means being so rotatable about the pin as
to bring the outwardly toothed portion to and out of a meshed engagement
with a part of the arcuate inwardly toothed portion of upper arm, to
thereby lock and unlock the upper arm with respect to the lower base arm;
an operation lever having a base end portion rotatably connected to the
shaft;
a biasing means for normally biasing the operation lever to a non-use
position; and
an interlocking means arranged between the lock gear means and operation
lever, the interlocking means including:
a cam means rotatably provided at the shaft, which has a cam end;
a guide means for guiding the lock gear means in a direction to disengage
the outwardly toothed portion of lock gear means from the arcuate inwardly
toothed portion of upper arm; and
a connecting means for connecting the cam means to the operation lever.
Accordingly, the motion of the lock gear means is confined to the rotation
about the pin, thus minimizing an annular clearance between the lock gear
means and pin to insure full meshed engagement between the outwardly and
inwardly toothed portions, without such wobbling problem as found in the
prior art.
Preferably, the pin associated with the lock gear means may be disposed
apart from the shaft, and the lock gear means be of an elongated shape
extending generally in a horizontal direction intersecting a diameter of a
circle along which the inwardly toothed portion is formed in the upper
arm.
In the foregoing interlocking means, the guide means may comprise a
projected guide portion formed on the lock gear means and an engagement
notch formed in the cam means, with such an arrangement that, when the
operation lever is at the non-use position, the engagement notch is
disengaged from the projected guide portion, whereas when the operation
lever is rotated about the shaft from the non-use position, the cam means
is simultaneously caused to rotate about the same shaft to bring the
engagement notch to engagement with the projected guide portion, and that,
with further rotation of the operation lever, the lock gear means engaged
with said engagement notch is caused to further rotate about the pin,
thereby bringing the outwardly toothed portion thereof out of meshed
engagement with the arcuate inwardly toothed portion of upper arm.
Otherwise, the guide means may comprise an arcuate guide hole formed in the
base end portion of operation lever and a projected guide portion formed
on the lock gear means, the projected guide portion being inserted
slidably through the guide hole, with such an arrangement that, when the
operation lever is at the non-use position, the projected guide portion is
positioned at one extremity of the arcuate guide hole to place the lock
gear means in the meshed engagement with a part of the arcuate inwardly
toothed portion, whereas when the operation lever is rotated about the
shaft from the non-use position, the projected guide portion is
simultaneously slid along the arcuate guide hole, thereby causing the lock
gear means to rotate about the pin, bringing the outwardly toothed portion
thereof out of meshed engagement with the arcuate inwardly toothed
portion.
According to one aspect of the invention, it may be so arranged that the
base end portion of operation lever is formed to expand upwardly, and the
above-mentioned arcuate guide hole is formed in the upper part of such
upwardly expanding base end portion, or alternatively it may be so
arranged that a link means is provided for linking the cam means to such
upwardly expanding base end portion of operation lever via the connecting
means, in order to amplify the rotation amount of both cam means and lock
gear means by a small rotation amount of the operation lever.
Other various features and advantages of the present invention will become
apparent from reading of the descriptions hereinafter, with reference to
the annexed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1(A) is a schematic diagram showing the construction of a conventional
reclining device;
FIG. 2(B) is a schematic diagram for explanatorily showing a wobbling
problem associated with the convention reclining device;
FIG. 2 is a partly broken schematic front view of a principal part of a
first embodiment of the reclining device in accordance with the present
invention, which also shows actions thereof;
FIG. 3 is an exploded schematic perspective view of the reclining device of
FIG. 2;
FIG. 4 is a partly broken cross-sectional view of the reclining device; of
FIG. 2
FIG. 5 is a partly broken schematic front view of a principal part of a
second embodiment of the reclining device in accordance with the present
invention,
FIG. 6 is a diagram showing a principle of actions of the reclining device
of FIG. 5;
FIG. 7 is a exploded schematic perspective view of the reclining device of
with FIG. 5; and
FIG. 8 is a schematic diagram showing a general principle of action in
accordance with the present invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION
Referring to FIGS. 2 through 8, there are shown referred constructions of
reclining device by way of example in accordance with the present
invention.
All through the embodiments in FIGS. 2 to 8, a basic construction of a
reclining device contemplated in the present invention comprises a
stationary lower base arm (12), a movable upper arm (14) rotatably
connected via a shaft (16) to the lower base arm (12), an inwardly toothed
portion (18) formed in the lower base arm (12), a generally horizontally
extending lock gear member (26) having a center of rotation disposed
eccentric with the axis of shaft (16), an operation lever (40 or 140)
rotatably connected to the shaft (16), and an interlocking means generally
designated by (Z), the interlocking means (Z) being arranged between the
lock gear member (26) and operation lever (40, or 140) such as to
interlock them together for the purpose of causing the lock gear member
(26) to be engaged with and disengaged from the inwardly toothed portion
(18), as will be elaborated concretely later.
This basic structure in accordance with the present invention is embodied
commonly in a first embodiment shown in FIGS. 2 to 4 and in a second
embodiment shown in FIGS. 5 to 7 with some modifications and additions
permissible within the gist of the present invention. Of course, these
embodiments are not limitative, and other further embodiments may be
adopted in various ways within the gist of the present invention.
FIG. 8 schematically shows a principle for locking action which is common
for both embodiments mentioned above in order to solve the unstable
locking problems stated in the description of prior art above. The details
thereof will become apparent later.
The upper and lower base arms (14) (12) are to be fixed to a seat back (SB)
and a seat cushion (SC), respectively, as with ordinary reclining devices,
which can be seen from the two-dot chain lines in FIG. 2.
Reference is now made to the first embodiments of the reclining device (10)
shown in FIGS. 2 to 4. In this mode, the upper arm (14) is best shown in
FIG. 3 as having a fan-shaped recessed area (14a) formed at the inward
side of the base end portion thereof. A connecting hole (20) is formed in
the inner flat surface (14a-2) of such recessed area (14a) at a point
corresponding to a center of rotation of the upper arm (14). The recessed
area (14a) has an arcuate wall (14a-1) defined along a circle whose center
is at that rotation center of upper arm (14). Further, and inwardly
toothed portion (18) is formed in that arcuate wall (14a-1 ), as shown.
The base arm (12) is also depicted in FIG. 3, which has a recessed area
(12a) formed at the inward side of upper half portion thereof. In the
recessed area (12a), there is perforated a bearing hole (17), a securing
hole (12a-1), and an arcuate elongated hole (42). Designation (12b)
denotes a circular recessed area which is opened at the outward side of
the base arm (12) for receipt of a circular flange portion (16c) of
support shaft (16). Thus, perforated in the bottom of that circular
recessed area (12b) is the foregoing bearing hole (17) through which the
support shaft (16) is inserted supportively. The arcuate elongated hole
(42) is defined immediate above the circular recessed area (12b) such as
to extend therealong in a concentric relation with the bearing hole (17)
on the other hand, the securing hole (12a-1) is disposed apart from those
two holes (17) (42) in an eccentric relation therewith.
As seen in FIGS. 3 and 4, the long shaft section (16a) of support shaft
(16) passes through the bearing hole (17) of base arm (12), and the
circular flange portion (16c) of same shaft (16) is fit in the circular
recessed area (12b) of lower arm (12), to thereby mount the support shaft
(16) in the base arm (12). Hence, a short split shaft section (16b) of
support shaft (16) opposite to the long shaft section (16a) projects
outwardly of the lower arm (12). An operation lever (40) is connected at
the base end part (40b) thereof to that short shaft section (16b) of
support shaft (16), such that the base end part (40b) of lever (40) is
rotatably supported, at its hole (40b-2), upon the short shaft section
(16b), allowing an opposite free end part (40a) of same lever (40) to be
rotated about the axis of support shaft (16). In this respect, the
operation lever (40) is formed, at its base end part (40b), integrally
with an inwardly extending horizontal connecting lug (40b-1) which forms a
part of the interlocking means (Z) to be explained later. The connecting
lug (40b-1) passes through the arcuate elongated hole (42), projecting
inwardly of the base arm (12). The operation lever (40) is prevented by a
snap ring (46) against removal from the shaft (16), the snap ring (46)
being firmly secured about the short split shaft section (16b) of shaft
(16). It is noted that the arcuate elongated hole (42) limits the
rotatable range of the operation lever (40).
As shown in FIG. 3, the operation lever (40) is provided with a spring (48)
secured to a securing piece (50) formed on the outside of lower arm (12),
and thus normally biased by the spring (48) downwardly towards a non-use
position as indicated by the two-dot chain line in FIG. 2.
A spiral spring (52) is further mounted on the outward side of lower arm
(12). As can be seen from FIGS. 3 and 4, the spiral spring (52) is
secured, at the central end (52a) thereof, in the split (16b-1) of short
shaft section (16b) associated with the shaft (16), via the foregoing snap
ring (46). Another end (52b) of the spiral spring (52) is secured on a
securing member (54) fixed to the upper arm (14).
The lock gear member (26) is formed in an elongated plate shape, which has
an outwardly toothed portion (24) oriented downwardly of the body of lock
gear member (26) and has a rotary connecting hole (29) formed at the base
end thereof. Thus, as shown in FIG. 3, the lock gear member (26) is
rotatably secured, at the hole (29) thereof, to the securing hole (12a-1)
of base arm (12) by way of a pin (30) fixed in the same securing hole
(12a-1). Thus, the lock gear member (26) is free to rotate vertically
relative to the pin (30) fixed in the securing hole (12a-1). It is noted
here from FIG. 2 that the lock gear member (26) is placed in a generally
horizontal state when its outwardly toothed portion (24) is in mesh with
the inwardly toothed portion (18) of upper arm (14), such as to transverse
the direction in which the inwardly toothed portion (18) is rotated, thus
providing a construction without any fore-and-aft wobbling of upper arm
(14) found in the prior art.
As shown, a protruded area (25) is formed in the planar side surface of
lock gear member (26). Also, an engagement lug (37) is formed in the upper
edge of lock gear member (26), projecting at a right angle therefrom on
the side where the protruded area (25) lies. Both protruded area (25) and
engagement lug (37) forms a part of the interlocking means (Z), which will
become understood later.
Designation (34) represents a cam plate which also forms a part of the
interlocking means (Z). As seen in FIGS. 3 and 4, the cam plate (34) is
rotatably supported, at the central hole (34b) thereof, upon the long
shaft section (16a) of shaft (16). The cam plate (34) has an upper
connecting hole (44) formed at the upper part thereof and a lower
engagement notch (38) formed at the lower part thereof. The connecting
hole (44) and engagement notch (3) are defined on the opposite sides of
the hole (34b), as illustrated. The hole (34b) of cam plate (34) is formed
with a cut-away region (60) into which a projected part (56a) of a
connecting tubular member (56) is to be inserted. The connecting tubular
member (56) is formed with an inner bore (56b) therein, into which the
long shaft section (16a) of support shaft (16) is to be inserted so that
the connecting tubular member (56) is supported rotatably on the shaft
(16) in a coaxial manner.
The upper arm (14) is rotatably supported, at the connecting hole (20)
thereof, upon the long shaft section (16a) of support shaft (16) by way of
a collar member (22). In this respect, the circular collar member (22) has
a circular projected portion (22a) slightly smaller in diameter than the
connecting hole (20) of upper arm, and further a connecting hole (22b)
having an arcuate cut-away region (58) defined partway circumferentially
thereof, through which arcuate cut-away region (58), the projected part
(56a) of connecting tubular member (56) passes. The arcuate cut-away
region (58) provides an escapement for allowing the projected part (56a)
of connecting tubular member (56) to be displaced freely with the rotation
of operation lever (40). Accordingly, the collar member (22) is secured on
the outward side of upper arm (14), with its circular projected portion
(22a) fitted in the connecting hole (20) of upper arm (14), and the upper
arm (14) is rotatably secured via the collar member (22) on the support
shaft (16) to thereby be attached rotatably to the base arm (12), with
both lock gear member (26) and cam plate (34) being interposed between the
two mutually faced recessed areas (12a) (14a) respectively of base and
upper arms (12) (14). Further, the projected part (56a) of connecting
tubular member (56) is inserted through the arcuate cut-away region (58)
of collar-member (22) (i.e. through the hole (20)) of upper arm (14)) and
fitted in the cut-away region (60) of cam plate (34).
Based on the above-described construction, referring to FIG. 2, in
accordance with the mechanical arrangements of present invention, when not
in use, the operation lever (40) is biased by the spring (48) to a
generally horizontal non-use position as indicated by the one-dot chain
line in FIG. 2. In this case, the interlocking means (Z) is so retained
under the biasing force of spring (48) as to keep the outwardly toothed
portion (24) of lock gear member (26) in a meshed engagement with a
predetermined part of the inwardly toothed portion (18). Namely, the
connecting lug (40b-1) integral with the operation lever (40) is biased
into contact with one extremity (42a) of the arcuate elongated hole (42)
of base arm (12), whereby the cam plate (34) connected with the connecting
lug (40b-1) is biasingly retained in the illustrated upright posture
generally perpendicular to the lock gear member (26). At this point, the
lower end (34a) of cam plate (34) contacts and applies a downward pressure
to the upper side (25a) of protruded area (25) of lock gear member (26),
whereby the lock gear member (26) is biased downwardly relative to the
axis of pin (30), placing its outwardly toothed portion (24) in a full
mesh with a part of the inwardly toothed portion (18) of upper arm (14).
In this non-use state, it is seen that the engagement notch (38) of cam
plate (34) is disengaged from the engagement lug (37) of lock gear member,
but positioned adjacent thereto.
Conversely, looking again at FIG. 2, when raising the operation lever (40)
in the upward arrow direction (UP) against the biasing force of spring
(48), the cam plate (34 ), i.e. one of the interlocking means (Z), is
rotated about the shaft (16) in the clockwise direction (L), whereby the
lower end (34a) of cam plate (34) is brought out of contact with the
protruded area (25, 25a) of lock gear member (26), and simultaneously, the
engagement notch (38) of cam plate (34) is brought in a hooking engagement
with the lug (37) of lock gear plate (26). With further upward raising of
the lever (40), the cam plate (34) is caused to rotate in further
clockwise direction (L), displacing onwards its notch (38) engaged with
the lug (37) of lock gear plate (26) in the same direction, whereby the
lock gear member (26) per se is caused by the cam plate (38) to rotate
further relative to the pin (30), bringing the outwardly toothed portion
(24) out of mesh with the inwardly toothed portion (18), as indicated by
the arrow (D). Thus, the upper arm (14) is free to rotate about the shaft
(16), allowing the seat back (SB) to be adjustably inclined forwardly and
backwardly relative to the seat cushion (SC) by raising and lowering of
the lever (40). Of course, to lower the lever (40) as indicated by the
arrow (LW) will cause (34) to rotate about the shaft (16) in the counter
clockwise direction (R), so that the lower end (34a) of cam plate (34) is
returned to the protruded area (25) of lock gear member (26), riding
thereon and applying a downward pressure thereto, while simultaneously,
the notch (38) of cam plate (34) is disengaged from the lug (37) of lock
gear member (26), thereby placing again the lock gear member (26) in a
full mesh with the inwardly toothed portion (18) of upper arm (14). In
this connection, it is preferable that the upper side (25a) of protruded
area (25) of lock gear member (26) should be sloped to facilitate smooth
riding thereon of the lock gear member lower end (34a), as illustrated.
Accordingly, referring to FIG. 8, it is appreciated that the motion of lock
gear member (26) is confined to a quite small amount of rotation about the
pin (30), and it is possible to minimize an annular clearance between the
pin (30) and the hole (29) of lock gear member (26), in contrast to the
two rectilinear clearances (R) (R) created in the prior art. Additionally,
the lock gear member (26) per se extends generally on a horizontal line
and intersects the direction in which the upper arm (14) is rotated about
the shaft (16), with the rotation center of lock gear member (26) disposed
eccentric with that of upper arm (14). This insures a full meshed
engagement between the outwardly and inwardly toothed portions (24) (18)
respectively of the lock gear member (26) and upper arm (14), and
therefore there is no such fore-and-aft wobbling of the seat back (SB)
found in the prior art. Further, even if the foregoing annular clearance
is reduced too extremely to increase a friction between the pin (30) and
hole (29), preventing smooth rotation of the lock gear member (26) about
the pin (30), the interlocking means (Z), especially the interlocking
actions between the cam plate (34) and lock gear member (26) as described
above, insure to apply downward and upward forces to the lock gear member
(26), enough to rotate the same (26) for engagement with and disengagement
from the inwardly toothed portion (18), overcoming such friction between
the pin (30) and hole (29).
Reference is made to the second embodiment of reclining device (110) shown
in FIGS. 5 to 6. In this mode, all the constituent elements are identical
to those of the foregoing first embodiment (10), that a slight
modification is made to the interlocking means (Z) and operation lever,
including addition of a link member (64) therein. Hence, specific
explanations are deleted with regard to the identical elements and parts
to those of the first mode (10) for the sake of simplicity in description.
Namely, as understandable from FIG. 7, an interlocking means (Z) according
to the present mode (110) differs from that of the first embodiment (10)
in that:
(a) A cam plate (34') is provided, which only differs from that (34) of the
first embodiment (10), in having no engagement notch (like (38) in FIG.
3);
(b) An outwardly projected pin (37') is formed on the outward side of the
lock gear member (26), as an equivalent to the engagement lug (37) of the
first mode (10), and an arcuate escapement hole (39) is formed in the
recessed area (12a) of base arm (12) in order to allow the pin (37') to be
freely slid therein;
(c) An arcuate elongated guide hole (38') is formed in the base end portion
(140b) of operation lever (140), as an equivalent to the engagement notch
(38) of the first mode (10); and
(d) A horizontally extending connecting lug (64a) is provided in a link
member (64), which is equivalent but identical in dimensions to that
(40b-1) of the first mode (10).
In the present mode (110), in addition to the foregoing interlocking means
(Z), the base end (140b) of operation lever (140) is so formed to expand
upwardly, and a link member (64) is arranged between that operation lever
base end portion (140b) and the outward surface of base arm (12).
The above-noted interlocking means (Z) in this particular mode are
therefore an alternative to the previously described interlocking means
(Z) of the first mode (10) for the common purpose of causing vertical
rotation of the lock gear member (26) for engagement with and
disengagement from the inwardly toothed portion (18). Specifically,
referring to FIG. 7, the projected pin (37') passes through both arcuate
escapement and guide holes (39) (38'). The arcuate escapement hole (39) is
formed to extend along a circle whose center is at the securing hole
(12a-1) of base arm (12), so that the projected pin (37') may be displaced
therealong to permit vertical rotation of the lock gear member (26)
relative to the pin (30) fixed in the securing hole (12a-1). The arcuate
guide hole (38') is defined at the upper end part of upwardly expanding
base end portion (140b) of operation lever (140) and formed in a shape of
"U" having a downward curvature, as best seen in FIG. 6. Such downward
curvature of guide hole (38') serves to cause the vertical rotation of
lock gear member (26) in cooperation with the rotation of the upwardly
expanding end portion (140b) of operation lever (140) about the pin (66)
through raising and lowering of the operation lever (140).
As likewise in the first mode (10), the cam plate (34') is rotatably
supported, at the hole (34b) thereof, upon the long shaft section (16a) of
support shaft (16), and has a connecting hole (44) formed at the upper end
thereof and a lower end (34'a) to be in a pressing contact on the
protruded area (25) of lock gear member (26).
The link member (64) is formed, at its upper end, with the horizontally
extending connecting lug (64a) equivalent to that (40b-1) of the first
mode (10). Also, the link member (64) has a first hole (64b) and a second
hole (64c) formed therein. As shown, the connecting lug (64a) of link
member (64) is inserted through the arcuate elongated hole (42') of base
arm (12) and fitted in the connecting hole (44) of cam plate (34'), while
the link member (64) per se is rotatably supported at the first hole (64b)
thereof, upon the short split shaft portion (16b) of support shaft (16).
The operation lever (140) is rotatably secured, at the hole (140c) thereof,
on the pin (66), such as to be rotatable about the pin (66) in the
vertical direction with respect to the base arm (12). A securing ring (78)
is fixed to the pin (66) to avoid separation of the operation lever (140)
from the base arm (12). In the upwardly expanding end portion (140b) of
this lever (140), there is further formed a connecting hole (76) in the
vicinity of the previously mentioned arcuate guide hole (38').
The link member (64) is interlocked to the upwardly expanding end portion
(140b) of operation lever (140), such that a pin (68) is inserted through
the second hole (64c) and connecting hole (76) respectively of the link
member (64) and operation lever (140). A securing ring (79) is fixed to
the pin (68) to avoid separation of the link member (64) and operation
lever (140) from each other.
Based on the above-described construction, referring to FIGS. 5 and 6, in
accordance with the mechanical arrangements of this second mode (110),
when not in use, the operation lever (140) is biased by the spring (48) to
a generally horizontal non-use position as shown in both FIGS. 5 and 6. In
this condition, the interlocking means (Z) is so retained under the
biasing force of spring (48) as to keep the outwardly toothed, portion
(24) of lock gear member (26) in a meshed engagement with a predetermined
part of the inwardly toothed portion (18). Namely, the connecting lug
(64a) connected via the link member (64) to the operation lever (140) is
biased into contact with one extremity (42'b) of the arcuate elongated
hole (42') of base arm (12), whereby the cam plate (34') connected with
the connecting lug (64a) is biasingly retained in the illustrated upright
posture generally perpendicular to the lock gear member (26). At this
point, the lower end (34a) of cam plate (34) contacts and applies a
downward pressure to the upper side (25a) of protruded area (25) of lock
gear member (26), whereby the lock gear member (26) is biased downwardly
relative to the axis of pin (30), placing its outwardly toothed portion
(24) in a full mesh with a part of the inwardly toothed portion (18) of
upper arm (14). In this non-use state, it is observed in FIG. 6 that the
outwardly projected pin (37') of the lock gear member (26) is positioned
not only in the right-side extremity (38'b) of arcuate guide hole (38'),
but also in the downward extremity of escapement hole (39). The connecting
hole (76) adjacent to the guide hole (38') is seen in the FIG. 6 to be
formed slightly in an elongated shape to provide an escapement to the pin
(68). It is noted that both extremities (38'a) (38'b) of arcuate guide
hole (38') limit the rotatable range of link member (64) and both
extremities (42'a) (42'b) of arcuate hole (42') limit the rotatable range
of the operation lever (140). The two holes (38') (42') are therefore
arranged in such a mutual relation as to determine a limit of operative
motion range of the operation lever (140). Conversely, viewing FIG. 6,
when raising the operation lever (140) in the upward arrow direction (U)
against the biasing force of spring (48), the arcuate guide hole (39)
having a downward curvature is displaced clockwise (R') relative to the
pin (66), which causes upward rotation of the pin (37') integral with the
lock gear member (26) along the arcuate escapement hole (39), so that the
lock gear member (26) is caused to rotate in the upward direction (D)
relative to the pin (30). Simultaneous with this motion, the lower end of
link member (64) is caused to rotate anticlockwise (R) about the shaft
(16) via the pin (68), which in turn causes the upper end of link member
(64) or the connecting lug (64a) to be displaced anticlockwise (L") along
the arcuate hole (42') of base arm (12). These interlocking actions, as
understandable from both FIGS. 5 and 6, result in the cam plate (34')
being simultaneously rotated together with the link member (64) in the
anticlockwise direction (R) relative to the shaft (16) and thus the lower
end (34'a) of same cam plate (34') is brought out of contact with the
upper side (25a) of protruded area (25) of lock gear member (26).
Accordingly, the lock gear member (26) is rotated upwardly relative to the
pin (30), thereby bringing its outwardly toothed portion (24) out of mesh
with the inwardly toothed portion (18), as indicated by the arrow (D).
Thus, the upper arm (14) is free to rotate about the shaft (16), allowing
the seat back (SB) to be adjustably inclined forwardly and backwardly
relative to the seat cushion (SC) by raising and lowering of the lever
(40). On the other hand, lowering the lever (40) as indicated by the arrow
(LW) causes the link member (64) to rotate about the shaft (16) in the
clockwise direction (L), while causing the arcuate guide hole (38') to be
displaced anticlockwise (L'). Such motions cause the lower end (34'a) of
cam plate (34') to again ride on the protruded area (25) of lock gear
member (26), applying a downward pressure thereto, while simultaneously
causing the lock gear member (26) to be displaced downwards (E) to place
its outwardly toothed portion (24) in a full mesh with the inwardly
toothed portion (18) of upper arm (14). In this connection, preferably the
upper side (25a) of protruded area (25) of lock gear member (26) should be
sloped to facilitate smooth riding thereon of the lock gear member lower
end (34'a), as illustrated.
Accordingly, the same advantageous effects as described in the first mode
(10) can be attained in this second mode (110) to avoid the unstable,
wobbling engagement between the lock gear and inwardly toothed portion
found in the prior art. In addition, according to the second mode (110),
the formation of upwardly expanding base portion (140b) in the lever (140)
and provision of the link member (64) may be effective in amplifying the
amount of displacement for both cam plate (34') and lock gear member (26)
by a small amount of vertical rotation of the free end portion (140a) of
operation lever (140). This is because, as understandable from FIGS. 5 and
6, the distance (l2) defined between the guide hole (38') and the rotation
center (at 66) of lever (140) may be adjustably longer to increase the
diameter of a circle along which the upper end of upwardly expanding base
portion (140b) of lever (140) is rotated relative to the pin (66), thereby
permitting the amount of displacement for the lock gear member (26) to be
amplified more by a smallest possible amount of vertical rotation of the
lever (140). Further, such distance (l2) also be adjustably greater than
another distance (l1) between the pin (68) and shaft (16) in order to
amplify the amount of displacement for the pin (68) relative to the shaft
(16). In other words, as shown in FIG. 6, the first distance (l2)
corresponds to a first diameter of circle along which the upper end of
operation lever base portion (140b) is rotated relative to the pin (16),
and the second distance (l2) corresponds to a second diameter of circle
along which the pin (68) is rotated relative to the shaft (16). Hence, by
making the first diameter (at l2) longer than the second diameter (at l2),
the rotation amount (.theta.2) of link member (64) may be amplified by a
small amount of rotation (.theta.1) of the lever (140), whereby the cam
plate (34') connected to the pin (68) may also be increased in amount of
rotation accordingly by rotating the lever (140) a small amount.
Consequently, the lock gear member (26) can be quickly brought out of
engagement with the outwardly toothed portion (18), while being quickly
released from the downward pressure of lower end (34'a) of cam plate
(34'), through a very small amount of upward rotation of the lever (140).
In both of the first and second modes (10) (110), it is further appreciated
that their respective interlocking means (Z) are provided coaxially on the
shaft (16) and require small number of constituent elements, so as to
simplify the structure of reclining device, and that the connecting
tubular member (46) may be rotated via their respective interlocking means
(Z) by the vertical rotation of operation lever (40 or 140). Although not
shown, the connecting tubular member (46) is connected to another
reclining device of the same construction describe above, so that the
rotation of the lever (40 or 140) may be transmitted thereto.
While having described the present invention thus far, it should be
understood again that the invention is not limited to the illustrated
embodiments, but other modifications, replacements and additions may be
structurally and mechanically applied thereto without departing from the
scopes of the appended claims. Naturally, it is a matter of design to
adopt one of the first and second modes (10) (110) and also to only choose
one of the two interlocking means (Z) or whether the action amplifying
means (64) (140b) may be added or not, from the understanding within the
scopes and definitions of the appended claims.
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